Oviposition Site Selection in Relation to Hatchling Feeding Performance in Two Sympatric <i>Papilio</i> Butterflies

ABSTRACT Females of many insect species do not care for their offspring after oviposition, and are expected to maximize their fitness by laying eggs on sites suitable for offspring survival and performance. The relationship between female oviposition and offspring performance has been widely examined in phytophagous insects, but its patterns vary by species and ecological context. Physical traits of host plants, such as leaf toughness, as well as chemical characteristics, may influence this preference–performance relationship and drive the adaptation of species‐specific larval feeding traits. In this study, we investigated oviposition site selection, egg and larval morphology, and hatchling performance in two sympatric swallowtail butterflies, Papilio xuthus Linnaeus and Papilio memnon Linnaeus (Lepidoptera: Papilionidae), that utilize Citrus trees as host plants. Our field work indicated that P. xuthus females tended to oviposit on smaller leaves located near branch tips, whereas P. memnon females laid eggs on larger leaves inside the canopy. Laboratory experiments revealed that P. memnon hatchlings had larger head capsules relative to egg size and larger mandibles relative to head size, and that their survival rates were higher, even on tough old leaves, than those of P. xuthus . These results suggest that the species have evolved unique relationships between maternal oviposition site selection and hatchling feeding traits in response to the microenvironments of their host plants.